Various studies on lactic acid bacteria or physiological effects of food products using lactic acid bacteria have been made since Metschnikoff's longevity theory.
As a function of lactic acid bacteria contained in fermented milk such as yogurt, for example, intestinal microflora improving effect, intestinal controlling action, etc. are well known. Recently, it has been reported that lactic acid bacteria have various functions such as immune activation action, antimicrobial action, antitumor action and the like. As described above, since various health effects are expected for lactic acid bacteria, fermented milk and lactic acid bacteria beverage using strains such as Lactobacillus acidophilus, Lactobacillus casei and genus Bifidobacterium, which are also detected in the human bowel, are put on the market.
By the way, active oxygen is important as a biological protection factor such as bactericidal action of leucocytes, but it becomes apparent that the excessive production of active oxygen in the living body causes various tissue disorders.
As the ordinary factors for generating active oxygen, there have been known stresses, alcohols, peroxides, drugs, exercises and the like. It is pointed out that active oxygen and lipoperoxide generated by these factors are closely connected with cerebral nerve diseases, circulatory diseases, cancers, alimentary diseases, hepatic diseases, arterial sclerosis, renal diseases, diabetes, aging and the like.
The living body retains a series of oxidation protection systems so to protect itself against oxygen toxicity. On the other hand, in order to permit these systems to function normally, it is important to ingest oxidation nutrient components sufficiently. As the natural oxidation nutrient components, there have been known vitamin E, vitamin C, s-carotene, polyphenol and trace elements (e.g. selenium, copper, zinc, etc.). For the purpose of affording an antioxidation action, food products containing these nutrient components have been developed.
In vivo antioxidation mechanism is classified roughly into a preventive antioxidation action (controlling the generation of a radical) and a linkage-breakage type antioxidation action (scavenging and eliminating a radical which has already been generated) according to its action. Examples of those which have the former action include enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and the like. Examples of those which have the latter action include the above antioxidation nutrient components.
However, in a conventional food product, there have never been known products which aim at conducting linkage-elimination of superoxide (O2−) and hydrogen peroxide (H2O2) which is connected with the lipid peroxidation.
It is an object of the present invention to provide an antioxidation food product, an antioxidation preparation and an antioxidation method for the linkage-elimination of superoxide and hydrogen peroxide, which express a superoxide dismutase (hereinafter referred to as “SOD”)-like activity and a catalase (hereinafter referred to as “CAT”) activity, simultaneously, and which are particularly superior in preventive antioxidation action.
The antioxidation food product of the present invention has an antioxidation action in the living body, comprising a fermented product produced by adding a manganese-containing natural material and fermenting with bacteria having a CAT activity. By “living body” is meant the physical body of living, multicellular organisms including, but not limited to humans and other mammals.
That is, the present inventors have obtained a knowledge that specific bacteria among various lactic acid bacteria express no CAT activity under the environment in which manganese is not present, but if manganese is present in the growing environment, they incorporate manganese into their cells to express a Mn-CAT activity and a SOD-like activity, simultaneously. The antioxidation food product of the present invention is particularly suitable as a preventive antioxidation food product.
It is known that Mn-CAT is not affected by various inhibitors, modifiers, chelating agents, etc. in comparison with heme-CAT containing iron, and exhibits stability within a wide range of pH and temperature.
Further, the antioxidation food product of the present invention may be a dried product, preferably a freeze-dried product which contains bacteria having a CAT activity and a manganese-containing natural material, in addition to the fermented product as described above by “manganese-containing natural material” is meant any material whether naturally occuring or synthetically produced which contains the element manganese bound to another organic or inorganic chemical moiety. The term is not meant to include elemental manganese.
The present invention also provides an antioxidation preparation comprising bacteria having a CAT activity and a manganese-containing natural material. This antioxidation preparation may be a dried product (in the form of tablet, powder, granule, capsule, etc.) or in the form of liquid.
Furthermore, according to the present invention, there is provided an antioxidation method in the living body including the interior of a digestive tract, which comprises ingesting a fermented product produced by adding a manganese-containing natural material to a food product and fermenting with bacteria having a CAT activity to express a SOD-like activity and a CAT activity, simultaneously.